A conventional robot hand, such as that disclosed in U.S. Pat. No. 8,388,035, is typically configured with a plurality of movable finger mechanisms for manipulation of a workpiece that is surrounded by the finger mechanisms. With a trend toward miniaturization, an end effector (e.g., a video camera, a suction plate, etc.) may be employed for assisting with the manipulation of the workpiece. However, the end effector may impose a spatial limitation on a workspace available for such manipulation, and an erroneous operation may easily occur due to obstruction of the end effector.